New terahertz device could strengthen security

November 21, 2014

We are all familiar with the hassles that accompany air travel. We shuffle through long lines, remove our shoes, and carry liquids in regulation-sized tubes. And even after all the effort, we still wonder if these procedures are making us any safer. Now a new type of security detection that uses terahertz radiation is looking to prove its promise. Able to detect explosives, chemical agents, and dangerous biological substances from safe distances, devices using terahertz waves could make public spaces more secure than ever.

But current terahertz sources are large, multi-component systems that sometimes require complex vacuum systems, external pump lasers, and even cryogenic cooling. The unwieldy devices are heavy, expensive, and hard to transport, operate, and maintain.

"A single-component solution capable of and widely tunable operation is highly desirable to enable next generation terahertz systems," said Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science at Northwestern University's McCormick School of Engineering and Applied Science.

Director of Northwestern's Center for Quantum Devices, Razeghi and her team have been working to develop such a device. In a recent paper in Applied Physics Letters, they demonstrate a room temperature, highly tunable, high power terahertz source. Based on nonlinear mixing in , the source can emit up to 1.9 milliwatts of power and has a wide frequency coverage of 1 to 4.6 terahertz. By designing a multi-section, sampled-grating distribution feedback and distributed Bragg reflector waveguide, Razeghi and her team were also able to give the device a tuning range of 2.6 to 4.2 terahertz at room temperature.

The device has applications in medical and deep space imaging as well as security screening.

"I am very excited about these results," Razeghi said. "No one would believe any of this was possible, even a couple years ago."

Explore further: Continuous terahertz sources demonstrated at room temperature

Related Stories

Continuous terahertz sources demonstrated at room temperature

June 5, 2014

Imagine a technology that could allow us to see through opaque surfaces without exposure to harmful x-rays, that could give us the ability to detect harmful chemicals and bio-agents from a safe distance, and that could enable ...

New technology illuminates colder objects in deep space

July 9, 2014

Too cool and faint, many objects in the universe are impossible to detect with visible light. Now a Northwestern University team has refined a new technology that could make these colder objects more visible, paving the way ...

Recommended for you

Two teams independently test Tomonaga–Luttinger theory

October 20, 2017

(—Two teams of researchers working independently of one another have found ways to test aspects of the Tomonaga–Luttinger theory that describes interacting quantum particles in 1-D ensembles in a Tomonaga–Luttinger ...

Using optical chaos to control the momentum of light

October 19, 2017

Integrated photonic circuits, which rely on light rather than electrons to move information, promise to revolutionize communications, sensing and data processing. But controlling and moving light poses serious challenges. ...

Black butterfly wings offer a model for better solar cells

October 19, 2017

(—A team of researchers with California Institute of Technology and the Karlsruh Institute of Technology has improved the efficiency of thin film solar cells by mimicking the architecture of rose butterfly wings. ...

Terahertz spectroscopy goes nano

October 19, 2017

Brown University researchers have demonstrated a way to bring a powerful form of spectroscopy—a technique used to study a wide variety of materials—into the nano-world.


Adjust slider to filter visible comments by rank

Display comments: newest first

2.3 / 5 (3) Nov 21, 2014
Instead of looking for religious nutjob artifacts, why not simply put religious nutjobs in separate screening and let rational people aboard freely?
not rated yet Nov 21, 2014
5 / 5 (1) Nov 21, 2014
Instead of looking for religious nutjob artifacts, why not simply put religious nutjobs in separate screening and let rational people aboard freely?

There are other kinds of "nutjobs" too; e.g. political extremists. The reason we're all screened is that such people can't be distinguished just by looking at them.
I would welcome the deployment of teraherertz scanners - I'm tired of the indignity of being patted down when the alarm sounds, even after I've removed shoes, belt, watch, coins and keys. I finally figured out it was my partial dentures (they have thick metal straps) so last trip I took them out, wrapped them in a tissue and put them in the tray with the shoes, belt etc. I got a few funny looks but at least the alarm didn't go off.
not rated yet Nov 21, 2014
I understand the appeal. If they could just screen everyone then they could potentially catch the ones who slip through the cracks and I'm totally fine with some security dude checking out my wang through his security imager but how would parents feel about the naked imaging aspect regarding children. If everyone gets scanned and they save the security footage for "national security reasons" then are they not generating their own form of child pornography? I've also read online that in the possibly near future police departments might get such a technology to scan from their patrol cars. Whats to stop them from imaging all the hotties? I'm a young man and I'm pretty sure you can guess what I'd do with x-ray vision. Just saying...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.